/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.mpp.plan.planner.plan.node;

import org.apache.iotdb.commons.exception.runtime.SerializationRunTimeException;
import org.apache.iotdb.consensus.common.request.IConsensusRequest;
import org.apache.iotdb.tsfile.utils.PublicBAOS;
import org.apache.iotdb.tsfile.utils.ReadWriteIOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.Objects;

import static java.util.Objects.requireNonNull;

/**
 * The base class of query logical plan nodes, which is used to compose logical query plan.
 */
public abstract class PlanNode implements IConsensusRequest {

    private final Logger logger = LoggerFactory.getLogger(PlanNode.class);

    protected static final int NO_CHILD_ALLOWED = 0;
    protected static final int ONE_CHILD = 1;
    protected static final int CHILD_COUNT_NO_LIMIT = -1;

    private PlanNodeId id;

    public PlanNode(PlanNodeId id) {
        requireNonNull(id, "id is null");
        this.id = id;
    }

    public PlanNodeId getPlanNodeId() {
        return id;
    }

    public void setPlanNodeId(PlanNodeId id) {
        this.id = id;
    }

    public abstract List<PlanNode> getChildren();

    public abstract void addChild(PlanNode child);

    @Override
    public abstract PlanNode clone();

    public PlanNode cloneWithChildren(List<PlanNode> children) {
        if (!(children == null
                || allowedChildCount() == CHILD_COUNT_NO_LIMIT
                || children.size() == allowedChildCount())) {
            throw new IllegalArgumentException(
                    String.format(
                            "Child count is not correct for PlanNode. Expected: %d, Value: %d",
                            allowedChildCount(), getChildrenCount(children)));
        }
        PlanNode node = clone();
        if (children != null) {
            children.forEach(node::addChild);
        }
        return node;
    }

    private int getChildrenCount(List<PlanNode> children) {
        return children == null ? 0 : children.size();
    }

    public abstract int allowedChildCount();

    public abstract List<String> getOutputColumnNames();

    public <R, C> R accept(PlanVisitor<R, C> visitor, C context) {
        return visitor.visitPlan(this, context);
    }

    public void serialize(ByteBuffer byteBuffer) {
        serializeAttributes(byteBuffer);
        id.serialize(byteBuffer);
        List<PlanNode> planNodes = getChildren();
        if (planNodes == null) {
            ReadWriteIOUtils.write(0, byteBuffer);
        } else {
            ReadWriteIOUtils.write(planNodes.size(), byteBuffer);
            for (PlanNode planNode : planNodes) {
                planNode.serialize(byteBuffer);
            }
        }
    }

    public void serialize(DataOutputStream stream) throws IOException {
        serializeAttributes(stream);
        id.serialize(stream);
        List<PlanNode> planNodes = getChildren();
        if (planNodes == null) {
            ReadWriteIOUtils.write(0, stream);
        } else {
            ReadWriteIOUtils.write(planNodes.size(), stream);
            for (PlanNode planNode : planNodes) {
                planNode.serialize(stream);
            }
        }
    }

    /**
     * Deserialize via {@link
     * org.apache.iotdb.db.mpp.plan.planner.plan.node.PlanNodeType#deserialize(ByteBuffer)}
     */
    @Override
    public ByteBuffer serializeToByteBuffer() {
        try (PublicBAOS byteArrayOutputStream = new PublicBAOS();
             DataOutputStream outputStream = new DataOutputStream(byteArrayOutputStream)) {
            serialize(outputStream);
            return ByteBuffer.wrap(byteArrayOutputStream.getBuf(), 0, byteArrayOutputStream.size());
        } catch (IOException e) {
            logger.error("Unexpected error occurs when serializing writePlanNode.", e);
            throw new SerializationRunTimeException(e);
        }
    }

    protected abstract void serializeAttributes(ByteBuffer byteBuffer);

    protected abstract void serializeAttributes(DataOutputStream stream) throws IOException;

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        PlanNode planNode = (PlanNode) o;
        return Objects.equals(id, planNode.id);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id);
    }
}
